U.S. patent number 4,642,263 [Application Number 06/683,435] was granted by the patent office on 1987-02-10 for antistat coated films.
This patent grant is currently assigned to American Hoechst Corporation. Invention is credited to Edwin C. Culbertson.
United States Patent |
4,642,263 |
Culbertson |
February 10, 1987 |
Antistat coated films
Abstract
Plastic films having improved antistatic properties are
disclosed having a continuous coating on at least one surface of
the film based on a composition comprising a mixture of: (a) a
polymeric binder, and (b) a quarternary ammonium salt having the
formula: ##STR1## wherein: R is a lower alkyl group having 1 to 3
carbon atoms; R' is an alkyl or alkenyl radical having from about 8
to 20 carbon atoms; and X.sup.- is an anion. The antistat coating
composition may be applied to the film material at any suitable
stage during manufacture, i.e., after extrusion of the sheet
material or before, during or after orienting the sheet. The
resultant film is found to possess markedly enhanced antistat
properties, good clarity, good slip properties, reclaimability and
adhesive properties at higher binder levels rendering it suitable
for the application of other coatings.
Inventors: |
Culbertson; Edwin C. (Greer,
SC) |
Assignee: |
American Hoechst Corporation
(Somerville, NJ)
|
Family
ID: |
24744032 |
Appl.
No.: |
06/683,435 |
Filed: |
December 18, 1984 |
Current U.S.
Class: |
428/336; 428/341;
428/412; 428/474.4; 428/480; 428/515; 428/518; 428/523 |
Current CPC
Class: |
C08J
7/044 (20200101); C08J 7/0427 (20200101); C08J
7/043 (20200101); C08K 5/19 (20130101); G03C
1/85 (20130101); C08J 7/046 (20200101); Y10T
428/31507 (20150401); Y10T 428/31938 (20150401); Y10T
428/31786 (20150401); Y10T 428/3192 (20150401); Y10T
428/265 (20150115); Y10T 428/31725 (20150401); Y10T
428/31909 (20150401); Y10T 428/273 (20150115) |
Current International
Class: |
C08J
7/04 (20060101); C08J 7/00 (20060101); G03C
1/85 (20060101); C08K 5/00 (20060101); C08K
5/19 (20060101); B32B 027/08 (); B32B 027/36 () |
Field of
Search: |
;524/331
;428/480,523,341,340,334-336,474.4,515,523,518,412 ;430/535
;252/8.8 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1079402 |
|
Aug 1967 |
|
GB |
|
1268780 |
|
Mar 1972 |
|
GB |
|
1411564 |
|
Apr 1972 |
|
GB |
|
1353076 |
|
May 1974 |
|
GB |
|
1558064 |
|
Feb 1976 |
|
GB |
|
Primary Examiner: Herbert; Thomas J.
Attorney, Agent or Firm: Lydon; James C. Tully; Michael
J.
Claims
What I claim is:
1. An oriented self-supporting plastic film having a thin
continuous antistatic coating on one or both sides thereof, said
coating comprising a mixture of:
(a) about 15% to about 50% by weight of a quaternary ammonium salt
having the formula: ##STR5## wherein: R is a lower alkyl group
having 1 to 3 carbon atoms;
R' is an alkyl or alkenyl radical having from about 8 to 20 carbon
atoms;
X.sup.- is an anion; and
(b) about 85% to about 50% by weight of a polymeric binder; said
coating being present in an amount effective to provide a film
having a surface resistivity not greater than about 10.sup.13
ohms.
2. The film of claim 1 wherein said plastic is selected from the
group consisting of polyester, polyamide, polystyrene,
polyethylene, polypropylene and polycarbonate.
3. The film of claim 2 wherein said coating has a dry thickness
within the range of about 10.sup.-7 to 10.sup.-5 inch.
4. The film of claim 1 wherein said plastic film is biaxially
oriented polyethylene terephthalate.
5. The film of claim 4 wherein R is methyl and R' is a radical of
about 14 to 18 carbon atoms derived from tallow fatty acid.
6. The film of claim 5 wherein said quarternary ammonium salt is N,
N, N, N.sup.1, N.sup.1 -pentamethyl-N.sup.1 -tallow
trimethylenediammonium-bis (methyl sulfate).
7. The film of claim 6 wherein said polymeric binder is selected
from the group consisting of acrylic or methacrylic polymers, vinyl
acetate polymers, vinylidene chloride polymers, and vinyl aromatic
polymers.
8. The film of claim 7 wherein said polymeric binder is a
crosslinkable acrylic or methacrylic polymer or copolymer.
9. The film of claim 8 wherein said polymeric binder is a
terpolymer of methyl methacrylate, ethyl acrylate and up to about
10 mole % acrylamide, methacrylamide, N-methylolacrylamide, or
N-methylolmethacrylamide.
10. The film of claim 8 wherein said polymeric binder is an acrylic
or methacrylic polymer or copolymer.
11. The film of claim 10 wherein said polymeric binder is a
crosslinked acrylic or methacrylic copolymer.
12. The film of claim 11 having an additional coating applied over
said antistat coating, said additional coating selected from the
group consisting of a printing ink, a matte drafting layer or a
light sensitive layer.
13. The film of claim 1 prepared by melt extruding said plastic to
form an amorphous film and thereafter orienting said film by
stretching in one or two directions and heat setting the film, said
antistatic coating applied to said film as an aqueous dispersion
prior to stretching in one direction or subsequent to stretching in
one direction but prior to stretching in a mutually perpendicular
direction, and drying said film.
14. The film of claim 13 wherein said plastic film is biaxially
oriented polyethylene terephthalate.
15. The film prepared by claim 14 wherein said film is subjected to
a corona discharge treatment prior to the application of said
antistatic coating.
16. The film of claim 14 wherein said quarternary ammonium salt is
N, N, N, N.sup.1, N.sup.1 -pentamethyl-N.sup.1 -tallow
trimethylenedi-ammonium-bis (methyl sulfate) present at a level of
about 10% to about 50% of said mixture.
17. The film of claim 16 wherein said coating has a dry thickness
of about 10.sup.-7 to 10.sup.-5 inch.
Description
BACKGROUND OF THE INVENTION
This invention is directed to an improved plastic film having
excellent antistatic properties and to a method for producing such
film. More specifically, the invention concerns improved biaxially
oriented polyester films having improved antistatic properties
coupled with altered surface properties which render the film
printable or coatable with additional coatings such as
photosensitive compositions.
The growth of the packaging, reprographic, microfilm and magnetic
tape markets has significantly increased the utilization of plastic
film materials in these fields, particularly biaxially oriented
plastic film made from polyethylene, polypropylene, nylon,
polyester, polystyrene and polycarbonate. One of the problems
associated with the use of such film is the tendency of these
materials to accumulate an electrostatic charge on the surface as
the result of handling or processing of the film, particularly at
low relative humidity. This electrostatic charge attracts not only
dust and other contaminants, but additionally attracts other film.
For instance, in the case of polyester film supports, electrostatic
charges may interfere with the collating, sorting and developing of
microfiche cards or transparent supports and cause these materials
to stick together.
To overcome this serious problem, antistatic films have been
developed. Antistatic films are usually formed by the application
of an antistatic coating onto the surface of the film. Many of
these coatings have successfully reduced the electrostatic
properties of the film to satisfactorily low levels. However, many
of these coatings can cause blocking. That is, the film coated with
an antistatic layer has a coefficient of friction high enough so
that one layer of the film does not slip over another or over
rollers and other equipment over which the film moves during
operation.
Another problem arising from the coating of an antistatic layer
onto a surface of a film is the decreased clarity resulting
therefrom. This property, usually reported as haze, is very
important in microfilm applications. Microfilm must be readable.
Light is projected through the film so that the viewer may read the
information printed on the film. Poor clarity results in fuzziness
and difficulty in reading because of loss of light intensity.
Yet a third problem associated with the application of an antistat
coating is its ability to remain adhered to the surface of the
film, particularly where the film is later treated with printing or
coating compositions.
Also important to the film manufacturer is the reclaimability of
scrap film produced during the film making process. Any coating
applied during manufacture will be present on the scrap film as an
impurity. This impurity can give rise to a discoloration as a
consequence of film reprocessing because of high temperature
conditions encountered in the film making process.
Various antistat coatings are disclosed in the prior art. For
example, U.S. Pat. No. 4,214,035 teaches the application to
polyester film of an antistat coating based on a mixture of
stearamidopropyldimethyl-beta-hydroxyethylammonium nitrate and a
crosslinkable acrylic terpolymer binder, present in an
approximately three to one ratio respectively. Although this
antistat coating improves the antistat properties of the film, the
relatively high level of antistat compound to binder renders the
coating relatively more expensive. Also, reclaim from such film
does exhibit discoloration when reprocessed into new film which is
undesirable, particularly where the film is to be used for
reprographic applications. Finally, the antistat surface of such
film is not readily susceptible to the application of additional
coatings, particularly in reprographic applications.
British Pat. No. 1,558,064 discloses the use of certain quarternary
ammonium salts as an antistat coating for polyolefin film such as
polypropylene. These salts have the formula: ##STR2## wherein A is
lower alkyl, R is an aliphatic radical having 1 to 22 carbons, x
and y are integers having the sum of 2 to 5, and X.sup.- is an
anion. The utilization of this material as disclosed in the patent,
aside from its effectiveness as an antistat, does not resolve the
problem of the lack of adhesion of additional coatings over the
antistat coating.
Accordingly, it is an object of this invention to provide plastic
film material having improved antistatic properties as well as good
blocking properties and low haze.
Another object is to provide a method for improving the antistatic
properties of biaxially oriented polyester film for use in the
graphic arts field.
Still another object is to provide an antistat coating on at least
one surface of biaxially oriented polyethylene terephthalate film
which coating also provides a suitable base coat or primer coat for
the application of additional coatings.
Yet another object is to provide a biaxially oriented plastic film
material having enhanced antistatic properties and which can be
successfully reclaimed in the plant by the film manufacturer.
SUMMARY OF THE INVENTION
These and other objects of the invention may be achieved by the
application of a continuous coating on at least one surface of a
plastic film material, said coating based on a composition
comprising a mixture of:
(a) a polymeric binder, and
(b) a quarternary ammonium salt having the formula: ##STR3##
wherein: R is a lower alkyl group having 1 to 3 carbon atoms;
R' is an alkyl or alkenyl radical having from about 8 to 20 carbon
atoms; and
X.sup.- is an anion.
The quarternary ammonium salt (QAS) compound and polymeric binder
may be present within a respective ratio of about 10 to 80% by
weight QAS per corresponding about 90 to 20% by weight of polymeric
binder on a dry weight basis, with the preferred level of QAS being
from about 25 to 75% by weight.
The antistat coating composition may be applied to the film
material at any suitable stage during manufacture, i.e., after
extrusion of the sheet material or before, during or after
orienting the sheet. The resultant film is found to possess
markedly enhanced antistat properties, good clarity, good slip
properties, reclaimability and adhesive properties at higher binder
levels rendering it suitable for the application of other
coatings.
DETAILED DESCRIPTION OF THE INVENTION
Film bases to which the present invention applies include
polyester, polyolefins such as polyethylene or polypropylene, nylon
(polyamide), polystyrene and polycarbonate. The invention is
particularly applicable to film based on crystallizable polyesters
such as resulting from the polycondensation of a glycol such as
ethylene glycol or butane diol and mixtures thereof with
terephthalic acid or mixtures of terephthalic acid and other
dicarboxylic acids such as isophthalic acid, diphenic acid and
sebacic acid, or their polyester forming equivalents, which
polyesters are made by methods well known in the art. The preferred
film base is polyethylene terephthalate and the invention will be
illustrated using this film.
The film may be produced by techniques also well known in the art
using well known apparatus. For example, polyester is melted and
extruded as an amorphous sheet onto a polished revolving casting
drum to form a cast sheet of the polymer. Thereafter, the sheet is
axially stretched in one direction, either in the direction of
extrusion (longitudinal), or perpendicular to the direction of
extrusion (transverse) in the case of monoaxially oriented film,
and in two directions in the case of biaxially oriented film, that
is, the film is stretched in both the longitudinal and transverse
directions. The first stretching step of the cast sheet may be in
either of these two orthogonal directions. The amount of
stretching, to impart strength and toughness to the film, can range
from about 3.0 to about 5.0 times the original cast sheet dimension
in one or both directions. Preferably, the amount of stretching is
in the range of between about 3.2 and 4.2 times the original
dimension. The stretching operations are carried out at
temperatures in the range of from about the second order transition
temperature to below the temperature at which the polymer softens
and melts.
Where necessary, the film is heat treated, after stretching, for a
period of time necessary to crystallize the polyester film.
Crystallization imparts stability and good tensile properties to
the film. When polyethylene terephthalate is heat treated, it is
subjected to a temperature in the range of between about
190.degree. C. and 240.degree. C. and, more preferably, in the
range of from about 215.degree. C. and 235.degree. C.
The antistat coating composition of this invention in the form of
an aqueous dispersion is preferably applied in-line at one of two
stages during the film manufacture: the pre-draw stage at the point
between the casting of the amorphous sheet and the first stretch by
the method disclosed, for example, in British Pat. No. 1,411,564 or
the inter-draw stage subsequent to the uniaxial drawing but prior
to biaxial drawing by the method disclosed, for example, in U.S.
Pat. No. 4,214,035. Normally, the heat applied to the film during
the stretching or final conditioning stages is sufficient to
evaporate off the water and other volatiles and dry the coating. In
some applications, the coating may also be applied to finished
film. This technique of application is less preferred because the
adhesion of the coating to the film is not as good as can be
achieved by in-line application.
In one preferred embodiment, the coating is applied after the film
is uniaxially stretched, that is, after the film is stretched in
one direction, but before the film is stretched in the orthogonal
direction. In another preferred embodiment, the polyester film is
first stretched in the longitudinal direction prior to coating. In
this preferred embodiment, after longitudinal stretching, the film
is coated by any of the well known techniques employed in the art.
For example, coating may be effected by roller coating, spray
coating, slot coating or immersion coating. In a preferred
embodiment, the polyester film is coated by means of gravure roller
coating. Also, the uniaxially drawn film is preferably subjected to
a corona discharge by a corona discharge apparatus prior to coating
as is known in the art. The discharge treatment decreases the
hydrophobic character of the polyester film surface which permits
the water based coating to more easily wet the surface and thus
improve the adhesion of the coating to the surface.
As indicated above under the Summary of the Invention, the antistat
composition comprises a mixture of a quarternary ammonium salt
compound having the recited formula and a polymeric binder. In the
preferred embodiment, the R substituent may be the same or
different throughout and is preferably methyl or ethyl; R.sup.1 is
a C.sub.14 to C.sub.18 residium of saturated acids, monoethenoid
acids, and diethenoid acids such as tallow, and X is chloride,
lower alkylsulfate or tosylate. The most preferred quarternary
ammonium salt is N, N, N, N.sup.1, N.sup.1 -pentamethyl-N.sup.1
-tallow trimethylenediammonium-bis (methyl sulfate) having the
formula: ##STR4##
These compounds and their method of preparation are disclosed in
U.S. Pat. No. 3,954,633, incorporated herein by reference. This
patent also discloses that the compounds are useful as lubricants
and antistatic agents to assist in the processing of natural and
synthetic fibers.
Suitable polymeric binders which may be used include acrylic or
methacrylic polymers such as polymethylmethacrylate, copolymers of
methyl methacrylate with acrylates such as ethyl acrylate or butyl
acrylate, and terpolymers of methyl methacrylate, ethylacrylate and
either acrylamide or methacrylamide, or either N-methylolacrylamide
or N-methylolmethacrylamide. In many cases it is desirable that the
polymeric binder be crosslinkable. This may be accomplished by
employing up to about 10 mole percent of a "self crosslinking"
functional comonomer into the binder, such as N-methylolacrylamide,
or by incorporating a suitable amount of cross linking agent such
as melamine formaldehyde or urea formaldehyde condensate capable of
reacting with a functional group present in the polymer chain, such
as amido, carboxyl, epoxy, or hydroxy groups. Other suitable
binders include vinyl acetate polymers such as polyvinylacetate and
copolymers based on vinylacetate, copolymers containing polymerized
vinylidene chloride, i.e., copolymers of vinylidene chloride,
acrylic ester and itaconic acid as disclosed in U.S. Pat. No.
2,698,240; and vinylaromatic polymers such as polystyrene and
copolymers containing polymerized styrene. Crosslinkable versions
of these materials may also be employed. The preferred binders for
the purposes of this invention are the crosslinkable acrylics, most
preferably acrylic terpolymers based on about 39 to 70 mole percent
methyl methacrylate, about 60 to 29 mole percent ethylacrylate, and
from about 1 to 10 mole percent of acrylamide, methacrylamide, or
N-methylolacrylamide. The acrylics offer the best balance of
antistat properties as well as good clarity, blocking resistance,
and reclaimability.
The antistat coating may contain from about 15 to 75% by weight of
the quarternary ammonium salt (QAS) compound and correspondingly
about 85 to 25% by weight of polymer binder on a dry weight basis.
This roughly corresponds to a respective range of 3 to 1 part QAS
compound per 1 to 5 parts polymer binder. It has been unexpectedly
found that with the acrylic binders, a respective ratio of as
little as 1 part of the QAS compound per 3.75 parts binder imparts
antistat properties to polyester film comparable to the properties
imparted by the antistat nitrates of U.S. Pat. No. 4,214,035
employed at a respective 3 part nitrate per 1 part binder ratio.
Use of higher ratios of the QAS compound, e.g., from about 1 to 1
up to about 3 to 1 imparts even better properties. Preferred ratio
of (QAS) compound to binder is about 25% to 75% by weight (QAS)
compound and about 75% to 25% by weight binder.
The antistat coating of the present invention may be applied to the
base film as an aqueous dispersion and at a solids concentration
within the range of about 0.5 to 15%, preferably about 1 to 8%. The
preferred solids level is such as to yield a final dry coating
thickness within the range of about 10.sup.-7 to 10.sup.-5 inch,
which translates into a solids level on a weight basis of from
0.00305g/m.sup.2 to 0.305g/m.sup.2. The preferred thickness range
of the dried coating is from about 1.0.times.10.sup.-7 to
3.0.times.10.sup.6 inch.
The antistat coating may be applied to one or both sides of the
film, or it may be applied to one side and a different coating such
as a thermosetting acrylic or methacrylic coating applied to the
opposite side, such as taught in U.S. Pat. No. 4,214,035. Other
additives known in the art may also be present in the coating
formulation such as wetting agents, surfactants, pH regulating
agents, anti-oxidants, dyes, pigments, slip agents such as
colloidal silica, and the like. Additives or polymeric binders
which lead to ion exchange type reactions with the quarternary
ammonium compound are to be avoided.
The antistat coatings of this invention exhibit excellent heat
stability. For example, scrap coated polyester film made during
production can be mixed with fresh polyester, remelted and refed to
the film-forming extruder to produce oriented film. Such film
produced containing up to about 50% by weight of coated scrap
reclaim (containing a heat stable binder such as an acrylic)
exhibits good quality, color and appearance with minimal
degradation of properties due to the presence of the coating
impurity. Thus the coated film of this invention can offer distinct
commercial advantage to the film manufacturer over many other
antistat films, such as films disclosed in U.S. Pat. No. 4,214,035,
which tend to degrade and discolor to a greater degree when
reclaimed as set forth above.
The ability to employ higher levels of binder with respect to the
amount of QAS in the coating composition and still maintain good
antistat properties renders film coated with the antistat
composition amenable to the application of additional coatings. For
example, polyester films coated with the antistat composition of
this invention which contain, as a binder, a crosslinkable acrylic
polymer present at a level of at least about 50% by weight,
preferably at least 65% by weight, has excellent utility as a film
base for the production of photosensitive reprographic films. Such
films are prepared by forming an additional coating on the surface
of the antistat coating present on the surface of the polyester
film, which additional coating comprises a photosensitive
composition containing an organic solvent solution of a resinous
binder containing or impregnated with a light sensitive diazonium
compound, and drying said coating. Resinous binders suitable for
this purpose include cellulose acetate butyrate, cellulose acetate,
cellulose acetate propionate as well as vinyl polymers such as
polyvinyl acetate. Suitable solvents include acetone, methyl ethyl
ketone, methyl isobutyl ketone, ethylene glycol monomethyl ether
and mixtures thereof. These reprographic coatings and their method
of application and use are well known in the art as used with other
base films.
Similarly such antistat coated film forms an excellent substrate
for the application of matte coatings which render the film
suitable for use as a drawing or drafting material. These matte
coatings may be based on organic solvent composition comprising a
resinous binder and a finely divided particulate material which
serves as a "toothing agent". The resinous binder may include the
resinous materials referred to above as well as acrylic or
methacrylic resins. The organic solvents may also include those
listed above. Particulate materials include finely divided (less
than 10 micron particle size) clays or silica. Other ingredients
such as thickeners or dispersing agents may also be present in such
matte formulations.
Yet another application of the antistat coated film of this
invention is as a packaging or label material. The coated films
demonstrate improved adhesion to printing inks when compared with
uncoated film.
The following examples are illustrative of the invention.
EXAMPLE 1
An aqueous dispersion of the antistat coating composition was
prepared by forming an intimate mixture of a water dispersion of N,
N, N, N.sup.1, N.sup.1 -pentamethyl-N.sup.1 -tallow
trimethylenediammonium-bis (methyl sulfate) and a polymeric latex
based on a crosslinkable terpolymer of methyl methacrylate, ethyl
acrylate and methacrylamide, also containing a sufficient amount of
a melamine/formaldehyde condensate to crosslink the polymer upon
the application of heat. The components were mixed to yield a ratio
of quarternary ammonium salt compound to polymer of about 1.3 to 1
on a dry weight basis. The dispersion was diluted with water to a
4% by weight solids level.
The above dispersion was applied to one side of polyester film as
follows:
Virgin polyethylene terephthalate polymer was melted and extruded
through a slot die onto a casting drum maintained at a temperature
of about 20.degree. C. The melt froze to form a cast sheet, and was
then longitudinally stretched at a draw ratio of about 3.6:1 while
maintaining a temperature of about 80.degree. C.
The longitudinally drawn film was corona treated by a corona
discharge apparatus and thereinafter coated with the latex
described above by gravure coating.
The corona treated, longitudinally drawn, coated film was dried at
a temperature of about 100.degree. C. Thereafter, the film was
stretched in the transverse direction at a draw ratio of 3.6:1 to
produce a biaxially drawn film. The biaxially drawn film was heat
set at a temperature of 230.degree. C. These heat treatments
resulted in the crosslinking of the primer coating. The dry weight
of the coating was about 0.035 g/m.sup.2 with a coating thickness
of about 1.times.10.sup.-6 inch and a base film thickness of about
3 mils.
The film prepared in Example 1 was evaluated for surface
resistivity at 50% RH using a Keithley Instruments electrometer
(Model 610B). Resistivity may also be measured in accordance with
ASTM Test D257-66. A control sample of uncoated 3 mil biaxially
oriented polyethylene terephthalate film was also evaluated. The
resistivity of the film of Example 1 was 2.times.10.sup.9 ohms; the
resistivity of the control was greater than 10.sup.16 ohms.
Surface resistivity of less than 10.sup.10 represents a film having
excellent antistatic properties, whereas a resistivity in excess of
10.sup.13 ohms is considered generally unacceptable. Preferable
resistivities achieved according to this invention are not greater
than about 10.sup.11 ohms.
EXAMPLES 2-28
Twenty three coated films were prepared as in Example 1 except the
respective solids levels of each component of the coating were
adjusted to give varying ratios of the quarternary ammonium salt
compound (designated as Q in Table 1) to acrylic polymer
(designated as A in Table 1) within the respective range of from
about 1.3:1 to about 1:3.75. The solids level of the coating
mixture was also adjusted to give different coating
thicknesses.
In Examples 25-28,
stearamidopropyldimethyl-beta-hydroxyethyl-ammonium nitrate
(designated as N in Table 1) was substituted for the quartenary
ammonium compound of Example 1 at a respective 3:1 dry weight
ratio.
As can be seen from a review of the data in the Table, the antistat
coating of the present invention imparts excellent antistat
properties to the polyester film, with the degree of enhancement
varying as a function of coating thickness and ratio of components
in the coating. Examples 25-28 illustrate that very high levels of
the tested prior art antistat and high coating thicknesses are
required to give results comparable to those films made in
accordance with this invention.
TABLE
__________________________________________________________________________
% REPRO- COATING THICKNESS SURFACE RESISTIVITY GRAPHIC EXAMPLE
FORMULATION (MICRO INCH) (OHMS AT 50% RH) ADHESION
__________________________________________________________________________
2 Q + A (1.3:1) 0.41 .sup. 3.3 .times. 10.sup.11 10 3 " 0.54 .sup.
1.6 .times. 10.sup.10 -- 4 " 0.71 5.0 .times. 10.sup.9 -- 5 " 0.61
2.4 .times. 10.sup.9 -- 6 " 0.66 1.8 .times. 10.sup.9 25 7 " 0.96
1.9 .times. 10.sup.9 -- 8 " 1.10 9.5 .times. 10.sup.8 25 9 Q + A
(1:1.5) 0.99 3.2 .times. 10.sup.9 60 10 " 1.30 2.4 .times. 10.sup.9
75 11 " 1.61 1.8 .times. 10.sup.9 100 12 " 2.03 1.2 .times.
10.sup.9 100 13 Q + A (1:2.25) 1.05 8.6 .times. 10.sup.9 70 14 "
1.28 4.9 .times. 10.sup.9 85 15 " 1.50 2.7 .times. 10.sup.9 100 16
" 1.93 1.9 .times. 10.sup.9 100 17 Q + A (1:3) 0.98 .sup. 2.7
.times. 10.sup.10 90 18 " 1.12 .sup. 2.7 .times. 10.sup.10 100 19 "
1.35 .sup. 8.9 .times. 10.sup.13 100 20 " 1.68 4.3 .times. 10.sup.9
100 21 Q + A (1:3.75) 0.91 .sup. 2.7 .times. 10.sup.13 75 22 " 1.36
.sup. 5.3 .times. 10.sup.12 95 23 " 1.81 .sup. 1.3 .times.
10.sup.10 100 24 " 2.04 .sup. 1.4 .times. 10.sup.11 100 25 N + A
(3:1) 1.02 .sup. 1.8 .times. 10.sup.11 0 26 " 1.18 .sup. 2.1
.times. 10.sup.10 10 27 " 1.69 7.8 .times. 10.sup.9 25 28 " 2.09
4.5 .times. 10.sup.9 25 CONTROL -- -- >10.sup.16 0
__________________________________________________________________________
The Table also illustrates the adhesive qualities of the coatings
of this invention when compared with uncoated film (control) and
the prior art film of Examples 25-28. The adhesive test is
conducted using a simulated reprographic lacquer comprising (in
parts by weight) 9 parts cellulose acetate butyrate of "20 second"
grade dissolved in a mixture of 88 parts ethylene glycol monomethyl
ether (methyl cellosolve) and 3 parts methyl ethyl ketone with
Rhodamine B dye added for color (3 parts of a 1% Rhodamine B dye in
n-butanol). The lacquer was applied to the coated surface of each
of the films tested by means of a wire-wound bar, Meyer rod No. 70,
and cured in an oven for 5 minutes at 60.degree. C. The coating was
scored with a cross-hatched pattern by means of a scalpel. A strip
of adhesive tape (Scotch tape 610) was adhered to the cross-hatched
area, rubbed with a fingernail to insure intimate contact and then
pulled rapidly from the film. The amount of lacquer remaining in
the cross-hatched area was expressed as a percentage of this
amount, i.e., no lacquer removed =100% adhesion, all lacquer
removed =0% adhesion with intermediate adhesion values being
assessed in terms of the proportion of lacquer area remaining
adhered to the film. The test was done twice on two sheets (total
of 4 areas tested) and the adhesion value reported as that of the
test area showing the most failure.
Test results demonstrating 95% adhesion or less are not generally
considered acceptable by commercial standards. Results of greater
than 95% to less than 100% are considered reasonably acceptable,
while test results demonstrating 100% adhesion are the target
standard for commercial acceptability.
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